Structural and multiferroic properties of epitaxial γ-Fe2O3–BiFeO3/Bi3.25La0.75Ti3O12composite bi-layers

Multiferroic properties of γ-Fe 2 O 3 –BiFeO 3 /Bi 3.25 La 0.75 Ti 3 O 12 epitaxial composite bi-layers grown on SrRuO 3 /SrTiO 3 (1 1 1) are compared with the properties of single phase BiFeO 3 and Bi 3.25 La 0.75 Ti 3 O 12 thin films. The composite bi-layers show well-saturated hysteresis loops with a low coercive field, a high fatigue resistance and high saturation magnetization. The insulating Bi 3.25 La 0.75 Ti 3 O 12 underlayer reduces significantly both the leakage current and the coercive field of the heterostructure (200 kV cm −1 ) at the expense of a lower polarization (20 µC cm −2 ), while the epitaxial γ-Fe 2 O 3 secondary phase that develops within the relaxed epitaxial BiFeO 3 matrix allowed for a high saturation magnetization.